1. Field of the Invention
The present invention relates to a cutting blade bending apparatus, and more particularly, the present invention relates to a cutting blade bending apparatus capable of precisely forming an acute angle.
2. Description of the Related Art
Various cutting blade bending apparatuses have been disclosed in the art.
First, referring to FIG. 7a, there is shown a transverse cross-sectional view of a cutting blade bending apparatus as described in International Publication No. WO95/0026. In this cutting blade bending apparatus, as a cutting blade 100 is moved forward by rotation of rollers 92 and 93 while passing through a guide opening defined in a fixed die 70, the cutting blade 100 is bent by virtue of a movable die 71 which is rotatably arranged around the fixed die 70. That is to say, as the movable die 71 is rotated, distal ends 711, 711 of the movable die 71 bias sideward the cutting blade 100 which is securely grasped by distal ends 700, 700 of the fixed die 70, and thereby, the cutting blade 100 is bent leftward or rightward. However, this conventional cutting blade bending apparatus is encountered with a problem in that an acute angle to which the cutting blade 100 can be bent, is limited to a certain value. Concretely speaking, when assuming that the cutting blade 100 is bent rightward to a great extent so as to finally form an acute angle with respect to a reference line, as the bent portion of the cutting blade 100 is brought into contact with the fixed die 70, the cutting blade 100 cannot be bent anymore, and it becomes difficult for the movable die 71 to apply strong biasing force to the cutting blade 100.
To cope with this problem, a cutting blade bending system as shown in FIG. 7b is described in U.S. Pat. No. 5,870,919. This system is different from the conventional cutting blade bending apparatus described above, in that a movable die can be positioned in front of a fixed die to allow bending members 80 to be freely moved and each bending member 80 of the movable die has a pin-shaped configuration. In this system, two bending members 80 are employed to respectively bend a cutting blade leftward and rightward. When a left bending member 80 biases a cutting blade rightward, a right bending member 80 is retracted into a rotating body 81 so as not to stand in the way of a bent portion of the cutting blade. However, the cutting blade bending system suffers from defects in that, when the cutting blade is bent rightward by the left bending member 80 to form an acute angle. If the right bending member 80 is extended to bend the cutting blade leftward in a state wherein the cutting blade is already bent beyond a position of the right bending member 80, the right bending member 80 cannot but be idly rotated. It is impossible to bend the cutting blade leftward. Such causes interruption of the entire system. Therefore, it is impossible to form an acute angle which is less than a predetermined degree.
Moreover, the bending members 80 are worn out due to repetitive retraction and extension, and a gap cannot but be created between the bending members 80 and edges of the rotating body 81. The edges define openings for guiding the retraction and extension of the bending members 80. Accordingly, when actually bending the cutting blade, the bending members 80 are not firmly supported by the rotating body 81, thus horizontal and vertical bending accuracies for the cutting blade cannot but be deteriorated.
A typical apparatus which employs only one bending member, is disclosed in U.S. Pat. No. 6,145,359 filed in the name of the present applicant. In this apparatus, after the bending member bend a metal plate in a clockwise direction, if it is necessary to bend the metal plate in counterclockwise direction, the bending member is retracted into a rotating body. The rotating body is further rotated in the clockwise direction to a position where the bending member can abut the other side of the metal plate and then the bending member is extended out of the rotating body. However, the apparatus still suffers from a drawback in that, since the rotating body must be rotated through a large angle in the clockwise direction to bend the metal plate counterclockwise, it is difficult to secure a wide area that provides a position between a guide section and the bent portion of the metal plate. Because of this, a controlling of the apparatus becomes complicated.
Further, this single-pin type apparatus is superior, in view of its acute angle forming capability to bend rule over a wider angle, over the aforementioned two-pin type cutting blade bending apparatuses, because one single bending number should sequentially bend the metal plate in the one and the other directions. However, it is not superior over the two-pin type cutting blade bending apparatuses in view of operational rapidity.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art. One aspect provides for a cutting blade bending apparatus that is capable of precisely forming an acute angle of a cutting blade and is excellent in view of operational rapidity and efficiency.
Another aspect provides a cutting blade bending apparatus which allows a cutting blade to be bent in a state wherein bending members are firmly supported by rotating bodies, thereby increasing horizontal and vertical bending accuracies for the cutting blade.
A further aspect provides a cutting blade bending apparatus comprising: a nozzle section for feeding a cutting blade into a bending area through a guide opening which is defined therein in a lengthwise direction of the cutting blade; a first bending member for bending the cutting blade fed into the bending area, in one direction; a second bending member for bending the cutting blade fed into the bending area, in the other direction; a first rotating body for firmly supporting the first bending member and guiding rotation of the second bending member; a second rotating body for firmly supporting the second bending member and guiding rotation of the first bending member, the second rotating body being rotated independent of the first rotating body; and a driving section for rotatably driving, at a time, one of the first and second rotating bodies.
By this feature of the present invention, the first bending member functions to bend the cutting blade in one direction, and the second bending member functions to bend the cutting blade in the other direction. Due to the fact that the first and second bending members are supported by the first and second rotating bodies, respectively, which are independently rotated of each other, rotating motion of the first bending member by the first rotating body and rotating motion of the second bending member by the second rotating body are independently implemented of each other. In the conventional art, since two bending members are supported by a common rotating body, a rotating angle of one bending member cannot but be restricted by the presence of the other bending member, whereby an acute angle cannot be adequately formed.
Also, in the present invention, because vertical movement of the first and second bending members as is the case with the conventional art, is unnecessary. Instead, the first and second bending members are rotated to bias the cutting blade while being firmly supported by the first and second rotating bodies. As a result, increased horizontal and vertical bending accuracies for the cutting blade can be accomplished, and operational rapidity can be ameliorated.
According to another aspect of the present invention, the nozzle section and the first and second rotating bodies are coaxially arranged one with another in a vertical direction, and the nozzle section passes through center portions of the first and second rotating bodies; the first rotating body comprises at least one pair of upper and lower rotating parts which are opposite to each other in the vertical direction with the guide opening of the nozzle section positioned between the upper and lower rotating parts and which are respectively defined with locking holes for firmly locking both ends of the first bending member and curved guide slots for guiding rotation of the second bending member; and the second rotating body comprises at least one pair of upper and lower rotating parts which are opposite to each other in the vertical direction with the guide opening of the nozzle section positioned between the upper and lower rotating parts and which are respectively defined with locking holes for firmly locking both ends of the second bending member and curved guide slots for guiding rotation of the first bending member.
By this feature of the present invention, the first rotating body comprises at least one pair of rotating parts which are separately positioned up and down. The second rotating body is configured in the same manner as the first rotating body. The first and second rotating bodies firmly support the first and second bending members, respectively. The first and second rotating bodies are defined with the curved guide slots for guiding rotation of the second and first bending members, respectively. The first and second rotating bodies and the nozzle section are concentrically arranged one with another. Accordingly, the first bending member which is firmly supported by the first rotating body, bends the cutting blade in one direction while being rotated along the curved guide slots defined in the second rotating body.
The second bending member which is firmly supported by the second rotating body, bends the cutting blade in the other direction while being rotated along the curved guide slots defined in the first rotating body. That is to say, a rotation angle of the second bending member is limited by the curved guide slots of the first bending member, and a rotation angle of the first bending member is limited by the curved guide slots of the second bending member.
In other words, the first rotating body provides the curved guide slots for guiding rotation of the second bending member which is not supported by it. This is of course, independent, in principle and time, of rotating motion of the first bending member which is actually supported by the first rotating body.
According to still another aspect of the present invention, each of the curved guide slots which are defined in the upper and lower rotating parts of the first rotating body, has one end corresponding to a bending standby position of the second bending member and the other end corresponding to a maximum bending position of the second bending member; and each of the curved guide slots which are defined in the upper and lower rotating parts of the second rotating body, has one end corresponding to a bending standby position of the first bending member and the other end corresponding to a maximum bending position of the first bending member.
By this feature of the present invention, in the cutting blade bending apparatus, after bending of the cutting blade in one direction is completed, the first bending member is returned to its bending standby position which is in the vicinity of a rear end of the nozzle section. At the same time, the second bending member which is in the bending standby position, can be rotated to bend the cutting blade in the other direction.
Also, as a matter of course, final rotation angles of the first and second bending members define the minimum acute angles which can be formed during the bending operation. Hence, the curved guide slots of the second rotating body for guiding rotation of the first bending member and the curved guide slots of the first rotating body for guiding rotation of the second bending member must be defined in a manner such that each curved guide slot has one end corresponding to the bending standby position and the other end corresponding to the maximum bending position (that is, a minimum acute angle forming position). In the present invention, the curved guide slots of the first and second bending members are symmetrically defined with each other.
According to yet still another aspect of the present invention, each of the first and second rotating bodies comprises at least two pairs of upper and lower rotating parts; upper rotating parts of the first and second rotating bodies are coaxially and alternately arranged one with another above the guide opening of the nozzle section; and lower rotating parts of the first and second rotating bodies are coaxially and alternately arranged one with another below the guide opening of the nozzle section.
By this feature of the present invention, since each of the first and second rotating bodies comprises at least two pairs of upper and lower rotating parts, and the rotating parts of the first and second rotating bodies are alternately arranged one with another, the bending members can apply stronger and uniform biasing force to the cutting blade, and thereby, precise vertical and horizontal bending of the cutting blade can be facilitated.